rcc is the file extension for saved MX-3000 files. mxf is the file extension for saved MX-850 files. I create and save as mxf because it is the "lowest common denominator" that can be used with any of the programmable remotes via the Universal Browser. BUT you can only drag and drop one command/function at a time to your MX-3000 layout - sorry! I'm glad you got everything working!
